scholarly journals Theoretical Investigation into the Ripple Source of External Gear Pumps

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 535 ◽  
Author(s):  
Xinran Zhao ◽  
Andrea Vacca
Keyword(s):  
Fluid Power ◽  
Flow Pulsation ◽  
Positive Displacement ◽  
System A ◽  
Novel Approach ◽  
Lumped Parameter ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
Increasing Demand ◽  
Good Interpretation

External gear pumps are among the most popular fluid power positive displacement pumps, however they often suffer of excessive flow pulsation transmitted to the downstream circuit. To meet the increasing demand of quiet operation for modern fluid power system, a better understanding of the ripple source of gear pumps is desirable. This paper presents a novel approach for the analysis of the ripple source of gear pumps based on decomposition into a kinematic component and a pressurization component. The pump ripple can be regarded as the superposition of the displacement solution and the pressurization solution. The displacement solution is driven by the kinematic flow, and it can be derived from the kinematic flow theory; instead, the pressurization solution can be approximated by overlapping the pressurization flow for a single displacement chamber. Furthermore, in this way the changes of these two components with modification of the delivery circuit are determined in both analytical and numerical ways. The result of this analysis provides a good interpretation of the pulsation simulated by a detailed lumped-parameter simulation model, thus showing its validity. The result also indicates that the response of two ripple sources to the change of the loading in the downstream hydraulic circuit is very different. These findings reveal the limitation of the traditional experimental method for determining the pump ripple, that new experimental methods which are more physics-based can be potentially formulated based on this work.

An Analysis of the Effects Causing an Asymmetric Behavior of the Lateral Lubricating Films of External Spur Gear Machines

2021 ◽  
Author(s):  
Kaeul Lim ◽  
Federico Zappaterra ◽  
Swarnava Mukherjee ◽  
Andrea Vacca
Keyword(s):  
Spur Gear ◽  
Common Assumption ◽  
Simulation Tools ◽  
Positive Displacement ◽  
Asymmetric Behavior ◽  
External Gear Pumps ◽  
Pressure Development ◽  
Gear Pumps ◽  
Set Up ◽  
Lateral Gaps

Abstract The torque efficiency and flow efficiency of positive displacement machines for fluid power applications are determined by the behavior of their internal lubricating interfaces. This aspect has motivated the development of tribological simulation tools for the analysis of these interfaces. The level of details these tools can provide allows explaining some counterintuitive aspects that occur in these interfaces. This paper focuses on a significant example, which is the high asymmetric behavior of the lubricating films occurring in pressure compensated external gear pumps. These units are often designed with a symmetric axial balancing compensation system. Notwithstanding, there are differences between the lateral gaps that can be explained only considering the mutual effects of the pressure development in the film and the material deformation. To study this problem, this paper utilizes the tool Multics-HYGESim developed by the authors’ research team. Two analyses are performed: the first one imposing axial symmetry in the behavior of the gap, which is the common assumption discussed in literature; the second one (referred to as “full configuration”), which holds the asymmetric behavior of the gap. An experimental set-up is used to validate the modeling assumptions based on the measurements of the drain leakage and volumetric efficiency. The main paper findings are on the uneven distribution of these leakages, which indicates an asymmetric behavior of the gap films in the unit.

The Flow Pulsation Analysis of an External Gear Pump

2011 ◽  
Vol 236-238 ◽  
pp. 2327-2331
Author(s):  
Yan Zhi Li ◽  
Li Huan Gao ◽  
Xiao Yang Tang
Keyword(s):  
Pulse Amplitude ◽  
Gear Pump ◽  
Flow Pulsation ◽  
Flow Ripple ◽  
Pump Flow ◽  
External Gear Pumps ◽  
Tooth Width ◽  
Different Types ◽  
Gear Pumps ◽  
External Gear Pump

In this paper, the theoretical flow ripple of an external gear pump is studied for pumps of similar size using different numbers of teeth on the driving and driven gears. External gear pumps with three different types of tooth profiles are studied. Nondimensional flowrates and fluctuation coefficients of gear pumps are discussed. By using the formula, flowrates can be calculated accurately and efficiently. Results indicate that: in the case of the same displacement (except teeth number and tooth width, other parameters of the gear pump are the same) the gear pump flow pulsation decreases with the increasing of the teeth number. We also concluded that changing tooth profiles on the driving and driven gear can get different pulse amplitude of the flow ripple.

Numerical Modeling of a Helical External Gear Pump With Continuous-Contact Gear Profile: A Comparison Between a Lumped-Parameter and a 3D CFD Approach of Simulation

2018 ◽  
Author(s):  
Xinran Zhao ◽  
Andrea Vacca ◽  
Sujan Dhar
Keyword(s):  
Cfd Simulation ◽  
Good Description ◽  
Helical Gear ◽  
Lumped Parameter Model ◽  
Fluid Power ◽  
Gear Pump ◽  
Continuous Contact ◽  
Positive Displacement ◽  
Lumped Parameter ◽  
Flow Features

The concept of continuous-contact helical gear pumps (CCHGP) has been proposed and successfully commercialized in the recent past. Thanks to the continuous-contact rotor profile design and to the helical gear structure, this design eliminates the kinematic flow oscillation. This has important implications on the fluid borne noise generation, which is considered as one of the major sources of noise emissions and mechanical vibrations for positive displacement machines. Although the commercial success of the CCHGP concept, there is very little published studies about the underling physics at the basis of the functioning of this type of design. This is mostly due to the complexity of the fluid domain that characterize the functioning of CCHGP units. In this paper, a transient 3D CFD study is conducted for a reference CCHGP unit for high-pressure (up to 200 bar) fluid power applications. The results of the 3D CFD simulation are compared with those given by a lumped-parameter model developed at the Maha Fluid Power Research Center of Purdue University (USA), which was previously validated against experimental results. The results show how with a proper discretization of the fluid domain the CFD simulation approach can be used for the case of helical CCHGP units. Both models provide a good description of the main features of operation of the unit. The lumped parameter model is quicker, thus suitable for fast optimization studies. However, the CFD results not only can be used to support the main assumptions done on the lumped parameter model, they also permit to gain further insight on the operation of the CCHGP unit, particularly with respect to the flow features of the meshing process.

The Research on the Theory of Flow and Method of Ripple Control of the External Gear Pump Group

2013 ◽  
Vol 706-708 ◽  
pp. 1827-1830
Author(s):  
Li Juan Yu ◽  
Xue Cheng Zhang ◽  
Xiao Dong Wang
Keyword(s):  
Quadratic Function ◽  
Gear Pump ◽  
Flow Pulsation ◽  
Amplitude Variation ◽  
Instantaneous Flow ◽  
Theory Of Flow ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
External Gear Pump ◽  
Ripple Control

In this paper, the theory of flow and method of ripple control of the external gear pump group are studied with two same-parameter external gear pumps which are installed in the form of parallel and different phase. In this thesis, the external gear pump group is known as a low ripple gear pump group, and the theory of ripple control is based on the theory that two periodic and quadratic function curves of different phase superposition can reduce the amplitude variation. According to this method, the thesis starts to analyze the instantaneous flow of the low ripple gear pump group, moreover which are compared with the instantaneous flow of a single gear pump. Finally, it is concluded that the flow pulsation rate of low ripple pump group is equal to 1/4 times of a single pump flow pulsation.

scholarly journals Lumped parameter model of vane pumps developed in OpenModelica environment

2021 ◽  
Vol 312 ◽  
pp. 05005
Author(s):  
Barbara Zardin ◽  
Giovanni Cillo ◽  
Marco Rizzoli ◽  
Massimo Borghi
Keyword(s):  
Flow Rate ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Dynamic Modelling ◽  
Physical Modelling ◽  
Lumped Parameter Model ◽  
Fluid Power ◽  
Vane Pump ◽  
Positive Displacement ◽  
Lumped Parameter

In this paper, the authors present a 0D fluid dynamic model of a vane pump used to refill tanks with fuel. The model is entirely developed in OpenModelica environment, where the authors have created specific libraries of elements suitable for the physical modelling of fluid power components and systems. Among the different approaches, the zero-dimension (0D) fluid-dynamic modelling of positive displacement machines is suitable to study many aspects as: the instantaneous flow rate, pressure and torque transients, the fluid borne noise related to the flow rate and pressure irregularity, the dynamic behaviour of the variable displacement control. Overall, this approach in modelling allows to link the geometrical features of the machine with its dynamic behaviour and for this reason is particularly useful in guiding the design. The model of the vane pump is described together with the main design features that can be analysed in terms of their influence on the pump behaviour. Besides the specific results obtained regarding the design of the pump, the paper also demonstrates the use of OpenModelica language and environment, and its efficacy, into the applications of fluid power modelling and simulation.

The Theoretical Research on the Third Planet Gear Flowmeter for Hydraulic System

2010 ◽  
Vol 20-23 ◽  
pp. 407-413 ◽  
Author(s):  
Jun Zhang
Keyword(s):  
High Pressure ◽  
Hydraulic System ◽  
Theoretical Research ◽  
Environmental Condition ◽  
Flow Pulsation ◽  
The Third ◽  
Positive Displacement ◽  
System A ◽  
Planet Gear ◽  
New Type

In connection with the situation that it is difficult to measure high-pressure flow in hydraulic system. A new type liquid flowmeter was designed in this paper, shown in Fig.1. The gear flowmeter is the positive displacement flowmeter with good features that the measurement precision is very accurate, and it is not restricted by environmental condition. But the gear flowmeter can't be widely used, just because its flow pulsation is large. After deeply studying the gear flowmeter, the author designed a new planet gear flowmeter. The flowmeter has the characteristics that the displacement is large, and the flow pulsation is small, even less than 1%. It can also be used to measure the flow in high pressure hydraulic system.

Design, Modeling and Analysis of a Gear Pump for Dispensing Application

2014 ◽  
Vol 592-594 ◽  
pp. 1035-1039 ◽  
Author(s):  
R. Hemanth
Keyword(s):  
Volume Flow Rate ◽  
Gear Pump ◽  
Modeling And Analysis ◽  
Positive Displacement ◽  
Critical Areas ◽  
External Gear Pumps ◽  
High Fructose ◽  
Gear Pumps ◽  
Available Technology ◽  
The Cost

Gear pumps are the most efficient positive displacement pumps that are being used in very high precision metering application and also with the cost of production of these pumps almost cut by a 25% to the conventional pumps, the external gear pumps have been a clear choice for the dispensing application in various industries. The design and modelling the concepts have been formulated using SOLIDWORKS modelling software and pump is aimed at delivering 20 bar of high fructose sugar syrup which will yield the required volume flow rate. Available technology was utilized in the design and fabrication of the external gear pump.[1] The design considerations and the relevant theories will affect the performance of the pump. The major factor in the pump being the nozzles that are being changed and what are the critical areas have validated using ABAQUS software.

Novel Approach of Improving Secondary Electron Detector in FIB System

2018 ◽  
Author(s):  
Steve Wang ◽  
Jim McGinn ◽  
Peter Tvarozek ◽  
Amir Weiss
Keyword(s):  
Integrated Circuit ◽  
Secondary Electron ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Vital Role ◽  
Electron Detector ◽  
System A ◽  
Novel Approach

Abstract Secondary electron detector (SED) plays a vital role in a focused ion beam (FIB) system. A successful circuit edit requires a good effective detector. Novel approach is presented in this paper to improve the performance of such a detector, making circuit altering for the most advanced integrated circuit (IC) possible.

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